For the crepes, place the water, milk, eggs, flour, salt, 1/4 cup butter, and the rosemary in a blender or food processor and blend well. Cover and refrigerate several hours. Thin the batter with water if necessary; it should be the consistency of very heavy cream.
Heat a crepe pan over medium-high heat. Brush the pan with melted butter and let it warm about a minute. Add a scant 1/4 cup batter and swirl it around in the hot pan. The crepe should be thin and set up almost immediately. Cook 1 minute, then flip it over either by turning it with your fingers or by flipping it into a second warm pan of slightly larger dimension. Cook the second side a moment, then turn the crepe out onto a towel. Brush the pan lightly with butter and make another crepe. As the crepes cool, you may stack them. There should be enough batter for 18 crepes. They can be held at room temperature for several hours before filling them; do not refrigerate.
Combine Fontina, mozzarella, Gruyere, ricotta, and pepper. Spoon about 3 tablespoons filling in the center of each crepe and roll up, tucking in the sides. Place on baking sheets lined with baker's parchment. These can be covered and refrigerated up to 2 days. If you think of it, let the crepes warm to room temperature before baking. Preheat the oven to 400 degrees F. Warm the bechamel and tomato sauces.
Butter 2 large baking dishes or individual gratin dishes. Spoon a layer of tomato sauce in the large dishes or about 3 tablespoons in each gratin dish. Place the filled crepes in rows in the large dishes or place 3 in each gratin dish. Spread the crepes with a layer of bechamel, then drizzle with a little more tomato sauce. Bake covered until hot, about 7 minutes. If the tops dry out, spoon a little more warm sauce over the crepes before serving. Sprinkle Parmesan if using. Serve at once.